Experimental analysis of drilling damage in thin carbon/epoxy plate using special drills

The aim of this study is drilling with a twist drill and a specific cutting tool of structural thin backing plates in carbon/epoxy. Drilling with a twist drill of the bolts' holes to fix a stiff plate reinforcement in front of the damage leads to defects and damages at the entrance, on the hole wall and at the plate exit. The possibility to manufacture carbon/epoxy with a conventional cutting tool was analysed and the limits of the twist drill were shown. Consequently we defined a specific cutting tool. Series of comparative experiments were carried out using a conventional twist drill and this specific cutting tool. The results showed the capabilities of the specific cuttings tool because several defects and damages usually encountered in twist drilled holes were minimised or avoided (entrance damage, roundness and diameter defects and plate exit damage). (C) 2000 Elsevier Science Ltd. All rights reserved.